The invention relates to a vessel system for the continuous monitoring of fluids, in particular industrial processes, preferably by means of NIR spectroscopy, having a vessel that is disposed in a subassembly support and has a sample chamber with an inlet opening and an outlet opening as well as a beam path directed toward a window of the sample chamber.
A vessel system of this kind has been disclosed, for example, by the European patent EP-B1-0 476 088 of the applicant.
Vessel systems of this kind are used for the online monitoring of fluids samples, in order to monitor the operation of systems. To this end, the sample is conveyed through a sample chamber that has a definite through flow gap, which is constituted by two disks that are spaced apart from each other. A beam of a light source is directed at the sample from one side and the beam is connected to a receiver on the other side, after it has passed through the sample. The composition of the sample can be deduced from the extinction of particular wavelengths.
In other systems, instead of the second disk, a reflective surface can also be used so that the composition of the sample can be deduced from the spectral composition of the reflected NIR (near infrared red) spectrum.
In order for reproducible measurement results to be produced, it is very important that the optical structure of the system does not get moved. Furthermore, the distance between the disks, i.e. the through flow gap or the layer thickness of the sample, has a significant influence on the measurement result. This layer thickness must also have the capacity for being set in a reproducible fashion. Finally, it is necessary to prevent deposits from forming on the measurement window which can also lead to distortions of the measurement result.
It is therefore important to carefully maintain systems of this kind and to clean them as needed.
Furthermore, the system must also be able to withstand the temperatures and pressures that prevail in harsh industrial operation in the manufacture of products, which need to be analyzed in an online fashion, i.e. continuously, by the system.
It also happens that different products are produced in the system to which the measuring device belongs. In such instances, it is necessary that the layer thickness can also be adapted to the medium to be analyzed.
Furthermore, is also necessary to measure reference samples with the system in order to calibrate the signal processing chain.
In the case of an instrument for laboratory operation, as is described in a product pamphlet of the applicant under the product name xe2x80x9cInfaPrime Labxe2x80x9d, a subassembly support is provided in a housing in which a standard glass vessel can be removed from the support and replaced by another standard vessel with a different layer thickness. As a result, it is possible to replace the vessel with a vessel that is similar, but is provided for other mediums.
In the support, therefore, the opening for the vessel is provided so that it is larger than would be necessary for most vessels. The gap in relation to the support, which gap is therefore produced with smaller dimensions, is bridged over by an adapter piece or a spacer.
With this embodiment, it has turned out to be disadvantageous that only standard laboratory vessels can be used. Furthermore, before the vessel replacement, the lines must be detached in an expensive manner. The housing is detached and rests on the table. Both the vessels and the supply lines are not suitable for industrial use. The medium to be analyzed must be supplied at low pressure by means of corresponding pumps, usually hose pumps.
By contrast, the system according to European patent EP-B1-0 476 088 is suitable for industrial conditions. A system of this kind is rigidly connected in the system by means of pipes. However, it must be disassembled in a very expensive manner for maintenance and must be carefully adjusted and installed in the system once again after maintenance. Particular care must be exercised in the fastening of light wave conductors since changes in the beam path, as explained above, can lead to distortions of the measurement result.
The object of the invention is to supply a system of the generic type mentioned at the beginning, which makes it possible to carry out monitoring under industrial conditions with a simplified maintenance.
This object is attained with a vessel system of this generic type by virtue of the fact that the subassembly support is disposed in a housing with a connecting armature that passes through the housing, wherein lines are provided between the connecting armature of the housing and the inlet and outlet openings of the sample chamber. The housing can consequently be rigidly installed in the system. All of the necessary pipelines of the system are rigidly connected to the housing.
The housing can advantageously be embodied in an explosion-proof manner so that the vessel system can also be used in an environment in which there is the danger of explosions. In order to perform maintenance or to replace the vessel, the connections inside the housing need only be detached and reassembled after the replacement of the vessel.
The replacement or maintenance of the vessel is embodied in a particularly simple fashion if the lines are embodied so that they can be detached quickly.
Additional assembly costs can be prevented if the vessel is embodied so that it can be removed as a subassembly from the subassembly support. By means of this, namely the connections of light wave conductors to the subassembly support can remain in place. A readjustment of the optics after the replacement of the vessel is advantageously eliminated since the subassembly support remains connected to the light wave conductors during the vessel replacement.
In terms of construction, it is sufficient for the rapid detachment of the line from the vessel if the line is comprised of an axially adjustable pipe end and a stationary pipe end that is preferably attached to the housing, which are embodied so that they can telescope in relation to each other.
Advantageously, the axial adjustment can occur by virtue of the fact that the line is embodied as a resilient tubular spiral and/or as an axially resilient bellows and/or as a resilient tubular meander and/or as a hose loop.
A knuckle joint is provided for rapid axial adjustment.
In an alternative embodiment, a spindle nut actuator is provided for the axial adjustment.
In particular applications in which particularly frequent maintenance is required due to the mediums to be analyzed and in which compressed air is already available in the system, it can be advantageous if a piston/cylinder drive mechanism is provided for the axial adjustment.
The measure that the subassembly support has an optical subassembly for the connection of a light wave conductor for the purpose of coupling and decoupling for radiation, permits a pre-assembly of the coupling and decoupling optics, for example for changed mediums. The optical conditions can be easily adapted to changed mediums or measuring methods, for example to a reflection measurement, through replacement of the optical subassembly.
Advantageously, the housing is embodied so that it is large enough for an assembly tool to be disposed in the housing. As a result, all of the tools required for replacement and for maintenance are always on hand. In addition to planned maintenance intervals, this also permits a maintenance or a replacement of the vessel to be carried out without incurring high costs.
The subassembly support can also be advantageously embodied so that the subassembly support has optical subassemblies for connecting a reference beam path. In order to improve measurement precision, before reaching its path through the sample, a reference beam is given an optical path that is largely equivalent to that of the measurement beam. As a result, influences of the optical components on the measurement result can be prevented through comparison of the signals.
If the sample chamber is embodied as guided, then optical conditions prevail which are always reproducible so that even after maintenance and assembly, a re-calibration can be advantageously eliminated.
The replacement is easier to carry out if a valve is integrated into the connecting armature.
An escape of the medium to be analyzed from the fixed piping into the housing is prevented if the valve is designed to close automatically when the line is detached.
When the medium to be analyzed is changed, the optical conditions for the measurement can be optimized by virtue of the fact that the through flow gap of the sample chamber is embodied so that can be adjusted. A spacer is disposed in the measurement chamber and reproducibly adjusts the gap for the through flow of the medium.
In particular instances it is advantageous that the sample chamber is embodied so that it is thermally insulated and/or temperature-stabilized, preferably by means of a temperature regulation. The this can be achieved, for example, by virtue of the fact that the contact surfaces in relation to the subassembly support are reduced to a minimum or else the sample chamber or the entire housing is kept at a constant temperature by means of a regulation.
The invention will be described in conjunction with a preferred embodiment form with reference to a drawing, wherein other advantageous details can be inferred from the figures of the drawing.